Reinforcement structure for disks



Filed Jan. 29, 1951 Jan. 10, 1956 s. A. LUNDGREN 2,730,265

REINFORCEMENT STRUCTURE FOR DISKS 2 Sheets-Sheet 1 Fig. 5a

Jam 1956 s. A. LUNDGREN REINFORCEMENT STRUCTURE FOR DISKS 2 Sheets-Sheet 2 Filed Jan. 29, 1951 F 1:9. 6 Zf30 7.3

United States Patent O 2,730,265 REINFORCEMENT STRUCTURE FOR DISKS Sven Ake Lundgren, Hultsfred, Sweden, assignor, by

mesne assignments, to American Heat Reclaiming Corporation, New York, N. Y., a corporation of New York Application January 29, 1951, Serial No. 208,285 12 Claims. (Cl. 220-71) This invention relates to a reinforcement structure for disks, for example disk shaped end covers for pressure vessels. The main object of the invention is to provide a reinforcement structure or reinforced disk of this kind which has to resist pressure stresses without being subjected to any considerable deformation.

An example of such a case is a spiral plate heat exchanger of the kind shown in U. S. Patent 2,360,739 in which the open sides of the spiral channels are sealed by means of disk-shaped covers, bearing against the circumferential edges of the spiral plates. It is a further object of the invention to provide a reinforcement for the covers of spiral plate heat exchangers of this general kind.

Obviously, the reliability of the sealing action will depend upon the condition that the contact pressure between the disk-shaped cover and the plate edges is maintained under all circumstances. If the disk is not stiff enough it will deflect axially outward under the influence of the pressure of the media in the channels, so that it may happen that the inner surface of the disk will be spaced from the edges of the spiral plates, especially in the central part of the apparatus.

In order to resist such deformation under the action of any considerable internal pressure in the apparatus the disk must be made very thick and heavy or reinforced by a stiffening structure of some kind. It has, for instance, been the practice to provide the disk with a structure of stiffening radial cross members welded to the outer surface of the disk. However, a stiffening structure of this nature does not afford any uniform support to the disk, so that the desired stiffening effect will not be obtained unless a comparatively large number of closely spaced cross members are provided or the section of the disk is made comparatively heavy.

It is a further object of the invention to provide an efficient reinforcing structure for disks of this and other kinds by utilizing a minimum of material and at the same time enabling the stresses in the disk to be distributed evenly and uniformly, especially along concentric circular paths.

According to one feature of the invention the reinforcing structure comprises at least two concentric ring elements of comparatively thin plate diverging axially towards and bearing directly or indirectly against said disk along their circumferential edges adjacent said disk element, said ring elements being interconnected along their opposite circumferential edges.

Further objects and advantages of my invention will be apparent from the following description, considered in connection with the accompanying drawing, which forms a part of this specification, and of which:

Fig. 1 is a sectional view, taken on the line I-I of Fig. 1a, of a disk structure in accordance with my invention;

Fig. 1a is a plan view of the structure shown in Fig. l;

Fig. 2 is a diametrical section of a second embodiment of the invention;

Fig. 3 is a diametrical section Fig. 4 is a diametrical section of the invention;

Fig. 5 is a diametn'cal section of a further embodiment;

Fig. 5a shows a part of Fig. 5 in a modified embodiment on a larger scale;

Fig. 6 is a sectional view taken on the line VI-VI of Fig. 6a of a spiral plate heat exchanger having diskshaped end covers reinforced according to my invention; and

Fig. 6a is a plan view, partly in cross section of Fig. 6 on the line VIaVIa.

In Figures 1 to So it is of the surfaces of the disk is subjected to a pressure or stress tending to deform the disk. In the figures this surface is assumed to be the lower one. In order to avoid such deformation I provide a reinforcing structure, preferably at the opposite surface of the disk 1, i. e. at the top surface shown in the figures. According to Figs. 1 and la this reinforcing structure comprises two concentric or approximately concentric shell shaped ring elements 2a, 2b of sheet metal or plate material which, at least partly, may have a substantially smaller thickness in radial direction than the thickness of the disk I. The outer ring 2b is cylindrical, and the surface of the inner ring 2a has the shape of a truncated cone. The surface of the conical ring 2a diverges from the surface of the cylindrical ring 2b in the direction towards the disk 1 or, in other words, the space between the two rings 2a, 2b increases in this direction. The ring elements are attached to the disk 1 directly or indirectly in a coaxial relation thereto so as to bear against the surface of the disk along one circumferential edge of each ring, and, for this purpose the ring 2b is Welded or soldered to the disk 1 along its edge at 3b while the ring 2a is welded or soldered to the disk along its edge at 3a. At the circumferential edges remote from the disk the rings 2a, 2b are interconnected by welding or soldering at X. The welding joints may be replaced by any other firm attachment. Alternatively the ring 2a may bear against the disk without being attached to it.

In the embodiment according to Figure 2 the inner ring M is cylindrical and the outer ring 2c conical. Along their circumferential edges abutting the surface of the disk 1 the rings are welded to the disk at 3a, 3b substantially as shown in Figures 1 and la. in Fig. 2 the part of the inner ring 2d remote from the disk 1 has a heavier section or, in other Words, is thicker in radial direction than the remaining part, so as to provide a stiffening annular head or ring 4a to which the ring element 20 is attached, for instance by means of a circumferential welding joint X as described with reference to Fig. 1. Of course, instead of, or in addition to providing the inner ring element 2a. with such a head or ring 4a the outer ring element 2c may be provided with such a head or ring.

In Fig. 3 both ring elements 2e, 2 have the shape of truncated cones but with the narrow ends of the respective cones pointing in opposite directions. One circumferential edge of each of the ring elements 2e, 2 is welded to the disk 1 at 3b, 3a as in Figs. 1 and 2. At the other circumferential edges the two ring elements are interconnected indirectly by means of an intermediate stiffening ring 4b interposed between the said edges and welded thereto at X. The apex angles of the cones may be equal or unequal. The intermediate stiffening ring 4b may also be applied in the case where one of the ring elements is cylindrical as in Figs. 1 or 2.

It is also possible to use more than two ring elements. As an example, Fig. 4 shows an embodiment with two pairs of ring elements 2h, 2k and 2l, 2g, respectively, all of conical shape, although one or more of them may be of a third embodiment; of a fourth embodiment assumed that in use at least one 7 3 cylindrical. As in the embodiment according to Figure 3 the ring elements are interconnected by means of a 'stifiening ring 4b coaxial with the ring elements. The apex angles of the conical rings of the pairs 2g, 21 and 2k, 2h, respectively, may be equal 'or unequa In the embodiment according to Fig. the reinforcing members comprise two concentric groups of conical rings 2m, 2n and 2p, 2/, respectively. The rings of each group diverge towards the disk 1. In each group the rings are interconnected indirectly by means of tubular stiffening rings 4c and 4d, respectively. The outer conical ring 2111 of the outer group is welded at 3b to the disk 1 along its circumferential edge 30, and the inner conical ring 2n of the same group is welded at 3a to the disk 1 along its circumferential edge 3d, while, in the inner group, the edge 3f of the outer conical ring 2p is welded to the disk at 3a and the edge 3g of the inner conical ring 21' at 38.

Figure 5a shows a modification of Figure 5 illustrating that it is not necessary to weld or firmly attach all conical ring elements to the surface of the disk, it being sufficient that the radially outermost ring is attached as above described and that the other rings bear against the disk at their abutting ends. As an example, Figure 5a shows that the conical ring eiernents 2n, 2,, at their abutting ends 3d, 3, engage the disk 1 without being fixed thereto, while said ends are interconnected by means of a welding joint 3h. in similar manner also the edge 3g of the conical ring 21' in Figure 5a may bear against the disk 1 without being Welded thereto. The conical ring 2m is welded to the disk 1 in the same manner as shown in Fig. 5. It should be understood that when the disk tends to deform, for instance into an upwardly convex configuration in Fig. 5a, the conical rings 2n, 2;}, 2r although not welded to the disk 1 will tend to counteract such deformation.

With respect to all embodiments shown, it is clearly seen that in any diametrical cross-section the disk 1 will be reinforced by the same reinforcing bridge structure in which the resistance of the circumferential interconnection or interconnections between the individual ring elements against deformation is sufiiciently great to permit dispensing with radial stiffening elements.

The reinforced disk according to my invention is particularly well suited for use as a cover for vessels, chambars or other apparatus in which the cover is subjected to stresses from pressure or vacuum within such vessel. Figs. 6 and 6a illustrate ah example of this kind. 7

Figs. 6 and 611 show a spiral plate heat exchanger 5 of the general type shown in U. S. Patent 2,360,739 having two separate spiral channels 6 and 7, each communicating with a separate central inlet or outlet 13 and 14, respectively. The channel 6 is closed at the bottom by a diskshaped cover 1b bearing against the lower edges 8a of the spiral plate 8 while the spiral channel 7 is closed at its top by a similarly shaped cover 1a, bearing against the top edges 9a of the spiral plate 9. Both covers are detachably secured to the apparatus by means of bolts 10. T he top cover In is provided with a reinforcement similar to the structure shown in Fig. 3 and the bottom cover 1b has a similar reinforcing structure but modified in that the outer conical ring element 2e is provided with, or attached to, a flange 11 through the intermediary of which it bears indirectly against the disk-shaped cover 1b and is fixed thereto by means of the bolts 10, while the inner conical ring element 2] along its circumferential edge adjacent the cover 11) is provided with a stiffening ring 12 through the intermediary of which it bears indirectly against but is not fixed to said cover 112. Thus, in the latter case not only the disk or cover 1b is detachable from the apparatus but also the reinforcing structure is detachable from the disk or cover 1b. If desired a gasket 15 may be interposed between the ends of the spiral plates 8, 9 and the covers 10, 1b.

From a study of Fig. 6 it will be app feciated that a structure accordingto the invention, in which diagonal reinforcing cross members are'dispensed with, will be especially well suited for the reinforcement of a disk having a central hole such as the inlets or outlets 13, 14.

The examples of embodiments here given are not to be regarded as exhaustive and it should be understood that the invention covers any further modifications which may be made without deviating from the scope thereof according to the appended claims.

What I claim is:

1. In a cover element for a pressure vessel comprising a substantially circular fiat disk element having one surface adapted to be subjected to the pressure in said vessel, a reinforcing structure for said disk element including at least two concentric substantially circular shell shaped ring elements diverging, as viewed in axial section, along substantially straight lines toward the opposite surface of said disk element, said ring elements reacting against said opposite side surface at their circumferential edges facing said disk element along concentric paths spaced in a zone extending from the peripheral portion of the disk element to the central portion thereof, said ring elements being interconnected along their circumferential edges remote from said disk element by means of a stiffening ring of substantially heavier dimension in radial direction than that of said ring element, said stiffening ring being interposed between and interconnected with said circumferential edges, at least the radially outermost of said concentric ring elements being firmly secured to said disk element.

2. A reinforcing structure as claimed in claim 1 in which at least the radially outermost one of said concentric ring elements is firmly secured to said disk element along the portion of said ring element abutting against said disk element and in which at least one of said remaining-ring elements is movable relative to said disk.

3. A reinforcing structure as claimed in claim 1 in which at least one of said ring elements along its circumferential edge adjacent said disk element is provided with a stiffening ring of radially heavier cross-section area than that of the plate wall of said ring element.

4. A reinforcing structure as claimed in claim 1 in which at least one of said ring elements is shaped as a truncated cone.

5. A reinforcing structure as claimed in claim 1 in which at least one of said ring elements is cylindrical and at least one other ring element is shaped as-a truncated cone.

6. In a structure for use as a cover element for a pressure vessel comprising a substantially circular fiat disk element having one surface adapted to be subjected to the pressure in the vessel, a reinforcing structure for said disk element including at least two concentric groups of shell shaped ring elements arranged in coaxial relation to said disk, each group including at least two concentric substantially circular ring elements diverging in axial section along substantially straight lines toward the opposite surface of said disk element, each ring element bearing at least indirectly against said opposite side surface with one of its circumferential edges along a path concentric to the corresponding bearing path of the other ring elements, the bearing paths of said ring elements being spaced in the zone between the peripheral portion of the disk element and the central portion thereof, the ring elements within each group being interconnected along their circumferential edges remote from said disk element by means of a stiffening ring of substantially heavier dimension in radial direction than that of said ring elements, said stiffening ring being interposed between and interconnected with said circumferential edges.

7. A reinforcing structure as claimed in claim 6 in which at least that one of said concentric ring elements of each group which is located radially outermost, is firmly secured to said disk along its circumferential edge abutting against said disk and in which at least one of said remaining ring elements is movable relative to said disk.

8; A reinforcing structure as claimed in claim 6 in which at least the radially outermost one of said concentric plate ring elements of the radially outermost group is secured to said disk along its adjacent edge, while radially adjacent groups are interconnected along their abutting circumferential portions. 9

9. A structure for sealing one end of channels of a spiral heat exchanger, having two spiral walls in radially spaced relationship forming between them two separate spiral channels, comprising a disk element having one side surface adapted to bear against one of the end edges of said spiral walls at least indirectly, a reinforcing structure for said disk element including at least two concentric substantially circular shell shaped ring elements diverging substantially straight toward the opposite side surface of the disk element, and hearing at least indirectly against said opposite side surface with their circumferential edges along concentric paths spaced from the peripheral portion of the disk element to the central portion thereof and being interconnected along their remaining circumferential edges by means of a stiffening ring of substantially heavier dimension in radial direction than that of said ring elements, said stiffening ring being interposed between and interconnected with said circumferential edges, at least the radially outermost of said ring elements being firmly secured to said disk element.

10. A cover for a pressure vessel comprising a disk, a first hollow frustum having a conical interior and exterior arranged with one base secured to said disk, a second hollow frustum having a conical interior and exterior and having one base of approximately the same size as the said other base of said first frustum, said second frustum being arranged with its said one base secured to said other base of said first frustum and the other base of said second frustum reacting against said disk, the surfaces of said first and second frustums diverging toward said disk.

11. A cover for a pressure vessel comprising a disk, a

first hollow frustum having a conical interior and exterior arranged with one base secured to said disk, a stiffening ring fixed to the other base of said first frustum, a second hollow frustum having a conical interior and exterior and having one base of approximately the same size as a portion of said stiffening ring and secured to said stiffening ring, said second frustum being arranged with its other base reacting against said disk and secured thereto, the surfaces of said first and second frustums diverging toward said disk.

12. A cover element for a pressure vessel comprising a disk for closing the end of the pressure vessel, a first hollow conical frustum secured with the edge of its larger base to one face of the disk, a second hollow conical frustum with its larger base substantially the same as the smaller base of the first frustum and secured to the free edge of the smaller base of the first frustum, the other edge of the second frustum being in engagement with the disk, the slant surfaces of the said cones divergin from their joined edges whereby a strong reinforcement is formed for said disk.

References Cited in the file of this patent UNITED STATES PATENTS Norway Apr. 25, 1949 

